Is a screening for Down's syndrome ...

Generally correct? I know occasionally there can be blips and false positives ... But generally is a high result a positive? I have a 1:27 chance of dc having downs. I have read conflicting info, but some say that getting such a high result generally suggests ds is inevitable - as the screenings are not 100% and a very high result should be taken as a highly likely.

I know this may sound confusing sorry, I am no expert on all this- I have been researching lots and as there are no answers as to why some Get such high results if baby doesn't have downs. So I am starting to believe it means in most cases a very high result such as mine is a 'more than likely' ...

For me it was my bloods giving me this high positive. The nt was 2.10- normal. I am mid twenties.

A result of 1:150 or less is considered high risk by the way. I think if I had a 1:100 it would be different - but our screening was relatively very high ...Aibu to believe that thiS 1:27 Is not a diagnostic, but a pretty cert dc will have downs....? Any feedback would be appreciated.

The combined test is not a diagnostic, as in it does not tell you whether the baby has Downs syndrome or not, it is a statistical test, as in it gives you a probability the baby might have the condition. The test has a very small chance of a false negative and about 5% chance of a false positive. Either way the test is not positive, it says that there is a one in 27 chance of the condition, which also means a 26 in 27 chance of not having it.

Have you considered an amniocentesis? That is a diagnostic test but does carry a 1:250 chance of causing a miscarriage.

You may also want to ask for your post to be moved to a more suitable board where you will get more answers.

It's a screening test - so they can not guarantee a yes / no answer. The probability of 1 in 27 puts you in the high category - are you having an amnio? I suppose the question is - do you want to know in advance and what would you do if the amnio was positive?

It certainly isn't a given that your baby will have downs. The only way to know for sure is to have an amnio or cvs. The blood screening can be affected by so many different factors. Women should really be counsellors well before the test about what they would do if the result was to show a high risk

After I very high result with ds I asked lots of questions on here and found stories of women who had been given high risk who went on to have children with out it however on there mext they had very low risk and had a child with ds.

Basically a one in 27 means, 1 woman in 27 with the same result will have a baby with ds.

I always wondered if high stress/depression affected my result and whether this was a true risk or if the stress/depression had actually had an effect on the baby

Thanks everyone. I am well aware that 1:27 mean a 26 babies won't have it and one will according to their stats. But I am seeing a lot of people with downs kids saying that a high risk is a high risk regardless and it is very likely. They haven't explained why though. Hence why I am here

Sorry of I haven't explained this clearly. I have been up since 5 with my dd !

My bloods came back with a 1 in 11 chance of Downs for ds2. I had an amino and it came back all clear. So, the test is not certain, but those few days between getting the news and getting the results from the amino were the most worried I have ever been in my life.

I chose not to have any screening but my son was born not with downs but another rare chromosome disorder which I have since read ds screening may have shown some soft markers for this probably isn't what you want to hear and I hope all your tests come back completely normal .

I don't understand what a false positive could mean in a system that only gives you a ratio chance of 1 in 2 at the highest, however..... OP - this most definitely does not mean your dc is likely to have ds.

What it means is that based on whatever historical cases were used to build the algorithm, women with the same nuchal and blood results as you would have one ds child for every 27 born. Or to look at it another way you are believed to have about a 96% chance of your baby not having downs.

Look into harmony testing. We did it recently as I was given a 1:37 chance. It's non invasive so no risks of miscarriage; it's done on the mother's blood and has a 1:10, 000 chance of giving the wrong result.

It's offered in a few nhs hospitals but otherwise it is rather expensive I'm afraid.

Good luck - it's a horrible time but chances are very definitely in your favour!

I read a lot about it, and there can be external factors upon the result. If you have been pregnant previously very soon before this pregnancy it can have an effect. Ditto bleeding in early pregnancy. There are others too. I will google.

I had a result of 1 in 64. Didn't have an amino due to previous late miscarriage and DS didn't have Down syndrome. My friend had a result of 1 in 8 and did have an amino and that came back negative. I didn't have the test with DS2.

I chose not to have any screening but my son was born not with downs but another rare chromosome disorder which I have since read ds screening may have shown some soft markers for this probably isn't what you want to hear and I hope all your tests come back completely normal .

Interestingly, DS does have a chromosome disorder we have since found out whereas DS2, who had a number of soft markers on the 20 week scan, doesn't have it! 20 years ago we wouldn't have known about either of these!!

My results were 1 in 250 & my son has Down syndromes he was that 1. Someone will have 1 in 2 but will not be the 1. Your baby has 26 chances not to be the 1 or 1 chance he or she will. Unless you have further testing you will not know for sure.

As I understand it 1 in 27 is high risk but not as high risk as some people get.

There is a 26/27 chance of your baby but having downs but that's not the same as everything bring ok. There are other conditions which would lead to higher risk results which would also figure in the 26/27.

Therefore if you get a 1 in 2 then most of the time there will be something wrong. 1 in 27 however I doubt that is the case and it is far more likely to be a false positive. 2.1cm nuchal is also above average so would raise your risk without it actually being anything to worry about as such.

If you are sampling people whose children were the 1 in 26 then of course they will say their risk translated to the condition. It doesn't make them wrong but what else are they going to say? If the tests were so wrong that 1/27 translated to a positive then we, as researchers, would adjust the scores to even higher. All the people you have spoken to have had their data added to the database and taking them into account gives you 1/27.

You are probably more likely to find stories from people who had 1/20 1/50 etc who did go on to have a diagnosis of down syndrome as it is relevant to their everyday lives, people who were in the 19/20 49/50 will probably not talk about their experience as often as it wasn't as relevant.